Method and apparatus for closing fissures in the annulus fibrosus

ABSTRACT

A filament laterally spans a tear, fissure or other defect in an annulus. One portion of the filament is anchored to the annulus by passing at least one first anchor through the annulus and into the nucleus on one side of the fissure, and with a second portion of the filament being anchored to the annulus by passing at least one second anchor through the annulus and into the nucleus on a second side of the fissure, with the at least one first and second anchors being drawn back through the nucleus and against the inner surface of the posterior annulus by the application of a significant (e.g., about 15N to 25N) axial tension applied perpendicular to the posterior wall of the annulus, and with the fissure being drawn closed by the subsequent application of a significant axial tension applied perpendicular to the posterior wall of the annulus.

REFERENCE TO RELATED APPLICATION

This application claims priority from U.S. Provisional PatentApplication Ser. No. 61/720,593, filed Oct. 31, 2012, the entire contentof which is incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to the treatment of intervertebral discherniation and degenerative disc disease in general and, moreparticularly, to methods and apparatus for closing fissures in theannulus fibrosus.

BACKGROUND OF THE INVENTION

The human intervertebral disc is an oval to kidney bean-shaped structureof variable size depending on its location in the spine. The outerportion of the disc is comprised of a tissue known as the annulusfibrosus (or annulus fibrosus, annulus fibrosis, annulus fibrosis, orsimply “the annulus”). The inner portion of the disc is comprised of atissue known as the nucleus pulpous, or simply “the nucleus”.

The annulus is made up of ten to twenty collagen fiber lamellae. Thecollagen fibers within a given lamella are parallel to one another.Successive lamellae are oriented in alternating directions. About 48percent of the lamellae are incomplete, but this value varies withlocation and it increases with age. On average, the lamellae lie at anangle of about 60 degrees to the vertebral axis line, but this toovaries with location. The orientations of the lamellae serve to controlvertebral motion (i.e., one half of the bands tighten to check motionwhen the vertebra above or below the disc are turned in eitherdirection).

The annulus contains the nucleus, which has a consistency generallysimilar to that of crabmeat. The nucleus serves to transmit and dampenaxial loads. A high water content (approximately 70-80 percent) assiststhe nucleus in this function. The water content has a diurnal variation.The nucleus imbibes water while a person lies recumbent. Nuclearmaterial removed from the body and placed into water will imbibe water,swelling to several times its normal size. Activity generates increasedaxial loads, which squeeze fluid from the disc. The nucleus comprisesroughly 50 percent of the entire disc. The nucleus contains cells(chondrocytes and fibrocytes) and proteoglycans (chondroitin sulfate andkeratin sulfate). The cell density in the nucleus is on the order of4,000 cells per microliter.

The intervertebral disc changes, or “degenerates”, with age. As a personages, the water content of the disc falls from approximately 85 percentat birth to approximately 70 percent in the elderly. The ratio ofchondroitin sulfate to keratin sulfate decreases with age, while theratio of chondroitin 6 sulfate to chondroitin 4 sulfate increases withage. The distinction between the annulus and the nucleus decreases withage. Generally, disc degeneration is painless.

Premature or accelerated disc degeneration is known as degenerative discdisease. A large portion of patients suffering from chronic lower backpain are thought to have this condition. As the disc degenerates, thenucleus and annulus functions are compromised. The nucleus becomesthinner and less able to handle compressive loads. The annulus fibersbecome redundant as the nucleus shrinks. The redundant annular fibersare less effective in controlling vertebral motion. This disc pathologycan result in: (1) bulging of the annulus into the spinal cord ornerves; (2) narrowing of the space between the vertebrae where thenerves exit; (3) tears of the annulus (both “full-thickness” and“partial-thickness” tears) as abnormal loads are transmitted to theannulus and the annulus is subjected to excessive motion betweenvertebrae; and (4) disc herniation or extrusion of the nucleus throughcomplete (i.e., full-thickness) annular tears. Degenerative disc diseaseis frequently the cause of substantial pain for a patient.

Current surgical treatments for disc degeneration are generally“destructive”, in the sense that they involve the removal or destructionof disc tissue. One group of procedures, which includes lumbardiscectomy, removes the nucleus or a portion of the nucleus. A secondgroup of procedures destroys nuclear material. This group includeschymopapin (an enzyme) injection, laser discectomy, and thermal therapy(i.e., heat treatment to denature proteins in the nucleus). The firsttwo groups of procedures compromise the nucleus of the treated disc. Athird group of procedures, which includes spinal fusion procedures,either removes the disc or eliminates the disc's function by connectingtogether two or more vertebrae, e.g., by “fusing” the vertebrae togetherwith bone. However, such spinal fusion procedures transmit additionalstress to the adjacent discs, which typically results in prematuredegeneration of the adjacent discs. In general, the “destructive” natureof current surgical treatments for disc degeneration can providesubstantial pain relief for the patient, but it can also lead to theacceleration of adjacent disc degeneration, which can result in new painfor the patient.

Prosthetic disc replacement offers many advantages. The prosthetic discattempts to eliminate a patient's pain while preserving the disc'sfunction. Current prosthetic disc implants either replace the nucleus orreplace both the nucleus and the annulus. Both types of implants requirethe removal of the degenerated disc component to allow room for thereplacement prosthetic component. Although the use of resilientmaterials has been proposed, the need remains for further improvementsin the way in which prosthetic components are incorporated into the discspace to ensure strength and longevity. Such improvements are necessary,since the prosthesis may be subjected to 100,000,000 compression cyclesover the life of the implant.

Current nucleus replacements may cause lower back pain if too muchpressure is applied to the annulus. As discussed in U.S. Pat. Nos.6,878,167 and 7,201,774, the content of each being expresslyincorporated herein by reference in their entirety, the posteriorportion of the annulus has abundant pain fibers.

Herniated nucleus pulposus occurs from tears (or “fissures”) in theannulus. The herniated nucleus material often applies pressure to thenerves or spinal cord. Compressed nerves can cause back and leg or armpain. Although a patient's symptoms result primarily from the pressurecaused by the herniated nucleus, the primary pathology lies in the tornannulus.

Surgery for the herniated nucleus, which is sometimes referred to as amicrolumbar discectomy, only addresses the herniated nucleus. With suchsurgery, the surgeon removes the herniated nucleus material, which ispressing on the nerves or spinal cord. In addition, in order to reducethe risk of extruding additional pieces of nucleus through the defect inthe annulus, the surgeon also generally remove generous amounts of thenucleus still within the annulus. However, this generally requires thatthe tear or fissure in the annulus be enlarged so as to allow thesurgeon access to the nucleus material still within the annulus, andthis enlargement of the tear or fissure further weakens the annulus. Asa result, while a microlumbar discectomy frequently decreases oreliminates a patient's back and leg or arm pain, the procedure typicallyfurther damages the already-weakened discs, which may lead to thecreation of future pain for the patient.

Thus there is a need for a new and improved method and apparatus forclosing fissures in the annulus.

SUMMARY OF THE INVENTION

This invention relates to the treatment of intervertebral discherniation and degenerative disc disease in general and, moreparticularly, to methods and apparatus for closing fissures in theannulus fibrosus (AF) or, simply the annulus (A). In one preferred formof the present invention, a first anchor component is inserted throughthe annulus and into the nucleus. Tension on the flexible longitudinalfixation component (e.g., the filament), in an axial direction, of forexample of 15N to 25N, pulls the anchor through the nucleus tissue andagainst the inner layer of the annulus. A second anchor component isthen inserted through the annulus, generally on the opposite side of adefect or fissure in the annulus and into the nucleus. Tension on theflexible longitudinal fixation component, in an axial direction, of forexample of 15N to 25N, pulls the anchor through the nucleus tissue andagainst the inner layer of the annulus. Such tension also pulls theflexible longitudinal fixation component through the opening or openingsin the second anchor, which increases the tension on the portion of theflexible longitudinal fixation component that extends between theanchors (lateral tension), which preferably pulls the annulus tissue oneither side of the fissure together.

Additional tension on the flexible longitudinal fixation component thenpulls a portion or portions of that flexible component into narrowslit-like openings in the anchor, which fastens those componentstogether. Additional anchor components, for example, three, four, five,or more anchors, which have flexible longitudinal fixation componentlocking or fastening features can be preferably placed in the disc usingthe same method. A single flexible longitudinal fixation componentpreferably connects such anchors. This approach eliminatespost-operative anchor migration through the nucleus, and thereby reducesthe tension across a fissure, and hence can allow nucleus material tomigrate into and through the fissure. Anchor components firmly seatedagainst the inner layer of the annulus, preferably in a sequentialmanner during surgery are not subject to such post-operative migrationand therefore maintain the desired tension across the fissure, whichprevents the migration of even small amounts of nucleus material into oracross the fissure.

The present invention may also be used to close other soft tissuedefects in the bodies of humans or animals. And the flexiblelongitudinal fixation components (e.g., the filaments) may be anchoredto one of the upper and lower vertebral bodies.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention will bemore fully disclosed or rendered obvious by the following detaileddescription of the preferred embodiments of the invention, which is tobe considered together with the accompanying drawings wherein likenumbers refer to like parts, and further wherein:

FIG. 1 is a schematic view showing one preferred form of apparatus forclosing a fissure in the annulus penetrating the annulus on one side ofa fissure;

FIG. 2 is a schematic view showing the apparatus of FIG. 1 ejected fromthe distal end of a needle-like insertion device;

FIG. 3 is a schematic view showing the apparatus of FIG. 2 pulledthrough nucleus tissue and against the inner layer of the annulus of anintervertebral disc;

FIG. 4 is a schematic view like that of FIG. 3, but showing theapparatus of FIG. 3 penetrating the annulus on a second side of thefissure;

FIG. 5 is a schematic view showing the apparatus of FIG. 4, but showingremoval of the needle-like insertion device closing the fissure in theannulus;

FIG. 6 is a schematic view showing the apparatus of FIG. 6 disposedagainst the inner surface of the annulus, and fastening of the tensionedflexible longitudinal component two the anchor components at leastpartially closing the fissure in the annulus;

FIG. 7 is a schematic view showing the apparatus of FIG. 1 disposedagainst the outer surface of the annulus;

FIG. 8 is a schematic view showing another preferred form of apparatusfor closing a fissure in the annulus;

FIG. 9 is a schematic view showing another preferred form of apparatusfor closing a fissure in the annulus near a vertebra;

FIG. 10 is a schematic view showing another preferred form of apparatusfor closing the fissure in the annulus;

FIG. 11 is a schematic view showing another preferred form of apparatusfor closing the fissure in the annulus;

FIG. 12 is a schematic view showing another preferred form of apparatusfor closing the fissure in the annulus;

FIG. 13 is a schematic view showing another preferred form of apparatusfor closing the fissure in the annulus;

FIG. 14 is a schematic view showing another preferred form of apparatusfor closing the fissure in the annulus;

FIG. 15 is a schematic view showing another preferred form of apparatusfor closing the fissure in the annulus;

FIG. 16 is a schematic view showing another preferred form of apparatusfor closing the fissure in the annulus; and

FIG. 17 is a schematic view showing another preferred form of apparatusfor closing the fissure in the annulus.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a new and improved method and apparatusfor closing fissures in the annulus. More particularly, the presentinvention facilitates the reconstruction of the annulus and, in somecases, the nucleus as well. Such reconstruction prevents recurrentherniation following a microlumbar discectomy. The invention may also beused in the treatment of herniated discs, annular tears of the disc, ordisc degeneration, while enabling surgeons to preserve the containednucleus. The method and apparatus of the present invention may be usedto treat discs throughout the spine, including the cervical, thoracic,and lumbar spines of humans and animals.

The present invention also enables surgeons to reconstruct the annulusand, if desired, to replace or augment the nucleus. Novel nucleusreplacements may be added to the interior of the disc. Annulusreconstruction prevents extrusion of the nucleus replacements throughfissures in the annulus. The annulus reconstruction prevents discherniation that may cause back and leg or arm pain. The nucleusreplacements may be made of natural or synthetic materials. Syntheticnucleus replacements may be made of, but are not limited to, polymersincluding polyurethane, silicon, hydrogel, etc., and/or other materialswhich may include elastomers.

The present invention is related to FIGS. 15A-15F of co-pending U.S.patent application Ser. No. 12/263,753, and FIGS. 5A, 5B, 42F ofco-pending U.S. patent application Ser. No. 13/297,789, which patentapplications are hereby incorporated herein by reference. Preferredembodiments of the present invention include one or more flexiblelongitudinal fixation components (e.g., filaments, sutures, etc.)extending across a soft tissue defect, such as a fissure in the annulus.One, two, three, four or more transverse anchor components (e.g., baranchors), connected to the one or more flexible longitudinal fixationcomponents, are preferably placed behind an inner layer of the annuluson opposite sides of the fissure, so as to anchor the one or moreflexible longitudinal fixation components to the annulus, with the oneor more flexible longitudinal fixation components extending axiallythrough the annulus and laterally across the fissure so as to hold thefissure closed, whereby to prevent nucleus material from passing out thefissure and pressing on the adjacent nerves, including the spinal cord.

Significantly, it has been discovered that applying significant tension(e.g., about 15N to 25N) to the flexible longitudinal fixationcomponents first in an axial direction substantially perpendicular tothe adjacent surface of the annulus, and then in a lateral directionsubstantially parallel to the adjacent surface of the annulus, providesa significantly improved closure of the fissure in the annulus. Moreparticularly, it has been discovered that applying significant tension(e.g., about 15N to 25N) to the flexible longitudinal fixationcomponents first in an axial direction substantially perpendicular tothe adjacent surface of the annulus pulls the transverse anchorcomponents through the nucleus tissue and securely against an innersurface of the annulus, in a sort of “pre-tension” action. Thereafter,applying significant tension (e.g., about 15N to 25N) in a lateraldirection substantially parallel to the adjacent surface of the annulusdraws the fissure closed in a sort of“closing tension” action.

Significantly, this serial application of a significant axialpre-tension, followed by a significant lateral closing tension, ensuresa tight closure of the fissure and hence raises the pressure required toextrude nucleus material through the fissure. Prior to this discovery,flexible longitudinal fixation components were secured at a maximum ofabout 6N tension, and even then in only a lateral directionsubstantially adjacent to the posterior surface of the annulus, whichfailed to pull anchor components through the nucleus tissue and againstthe inner layer of the annulus tissue. Such failure resulted in arelatively loose closure of the fissure, which enabled nucleus materialto extrude through the fissure.

It has further been discovered that, by increasing the tensile forceapplied to the flexible longitudinal fixation components to about 15N to25N, and by sequentially applying the tensile force first in an axialdirection substantially perpendicular to the adjacent surface of theannulus (i.e., in a pre-tension action) and thereafter in a lateraldirection substantially adjacent to the posterior surface of the annulus(i.e., in a closing tension action), the efficacy of the closure issignificantly increased, and the force required to extrude nucleusmaterial through the closed fissure is significantly increased.

By way of example but not limitation, it has been found thatsequentially applying about 15N to 25N of tensile force to the flexiblelongitudinal fixation components, first in an axial directionsubstantially perpendicular to the adjacent surface of the annulus andthen in a lateral direction substantially parallel to the adjacentsurface of the annulus, increases by 64% the force required to extrudenucleus material through the fissure, as compared to conventionalclosures effected with flexible longitudinal fixation components usingabout 6N of tension applied in the single, “parallel-to-the-annulus”direction of the prior art.

For the purposes of clarity of description, the present invention willhereinafter generally be discussed in the context of closing a tear orfissure formed in the posterior annulus of an intervertebral disc,however, it should be appreciated that the present invention is alsoapplicable to closing a tear or fissure formed in another portion of theannulus of an intervertebral disc, or to closing a tear or fissure orother opening formed in another anatomical structure, etc.

FIG. 1 is a schematic view showing apparatus 101 for closing a fissure Fin the annulus fibrosus, or “annulus” (A). Apparatus 101 generallycomprises cylindrical transverse anchor components (e.g., bar anchors)102, 104 (FIG. 4) that are slidably mounted on a flexible longitudinalfixation component (e.g., filament, suture, etc.) 110. The flexiblelongitudinal fixation component 110 passes through one or more holes ineach transverse anchor component 102, 104.

The transverse anchor components 102, 104 are preferably about 0.8 to 2millimeters in diameter, and most preferably about 1.1 to 1.3millimeters in diameter, and about 3 to 7 millimeters in length, andmost preferably about 4 to 5 millimeters in length. The holes intransverse anchor components 102, 104, 106, 108 are preferably about 0.1to 0.8 millimeters in diameter, and most preferably have a narrowportion of about 0.1 to 0.3 millimeters in diameter and wider portion ofabout 0.4 to 0.8 millimeters.

The proximal and distal portions of the holes in transverse anchorcomponents 102, 104 are preferably beveled, or have rounded edges, so asto reduce friction between flexible longitudinal fixation component 110and the transverse anchor components 102, 104, and so as to reduce therisk of the edges of the holes cutting the flexible longitudinalfixation component 110. The transverse anchor components 102, 104 arepreferably cylindrical, but may be elongate with a non-circularcross-section in alternative embodiments of the invention. For example,such transverse anchor components 102, 104 may have triangular, square,hexagonal or other shapes in cross-section. Two or more transverseanchor components 102, 104 (e.g., 4 to 8 such transverse anchorcomponents) may be provided for each flexible longitudinal fixationcomponent 110 in alternative embodiments of the invention.

The transverse anchor components 102, 104 may be made of titanium,tantalum, stainless steel, polypropylene, Delrin, polyetheretherketone(PEEK), or any other suitable biocompatible material. By way of examplebut not limitation, the transverse anchor components 102, 104 may bemade of molded PEEK.

The flexible longitudinal fixation component 110 is preferably formedout of suture, e.g., size 2-0 to #4 non-absorbable suture, and mostpreferably size 2-0 or 1-0 suture. By way of example but not limitation,the flexible longitudinal fixation component 110 may be made of size 2-0braided suture such as Ethibond (Ethicon, Somerville, N.J.), FiberWire(Arthrex, Naples, Fla.), MaxBraid (Biomet, Warsaw, Ind.), and Orthocord(DePuy, Warsaw, Ind.). The flexible longitudinal fixation component 110is preferably about 40 to 120 centimeters long, and most preferablyabout 70 to 95 centimeters long.

The apparatus 101 loaded in the distal end 120 of a needle-likeinsertion device 122. The longitudinal axes of the transverse anchorcomponents 102, 104, which are co-linear and most preferably co-axialwith one another, are loaded in the distal end of the lumen ofneedle-like insertion device 122. Such needle-like insertion device 122is described and illustrated in the aforementioned U.S. patentapplication Ser. Nos. 12/263,753 and 61/414,186, both of which areincorporated herein by reference. The ends and the central portion ofthe flexible longitudinal fixation component 110 extend into the lumenof the needle-like device 122 or out through a slot formed in the sideof the distal end 120 of the needle-like insertion device 122.

As shown in FIG. 1, the distal end 120 of needle-like insertion device122 is advanced through the annulus A of the intervertebral disc D onone side of a tear or fissure F and into the nucleus tissue N. A styletcomponent 127 slidably disposed in the lumen of the needle-likeinsertion device 122 forces the first transverse anchor components 102out of the distal end of the needle-like insertion device 122 after thedistal end of the needle-like insertion device 122 has passed throughthe annulus A on a first side of a fissure F in the annulus. The endsand central portion of the flexible longitudinal fixation component 110are seen extending through the hole in the posterior annulus created bypassage of the needle-like insertion device 122.

When the first transverse anchor component 102 is ejected from thedistal end of the needle-like insertion device 122 into the nucleus N ofthe intervertebral disc D, the distal end of the needle-like insertiondevice 122 must have been advanced a sufficient distance into thenucleus N for the first transverse anchor component 102 to be able toturn (i.e., from the longitudinal orientation of FIG. 1 to thetransverse orientation of FIGS. 4, 5 and 6) so as to prevent the firsttransverse anchor components 102 from being pulled back through theposterior annulus. Note also that at this level of penetration into thenucleus N, a substantial amount of nucleus material will be interposedbetween the first and transverse anchor component 102 and the innersurface of the posterior annulus.

FIG. 2 is a schematic view showing the apparatus 101 in the nucleustissue and the needle-like insertion device 122 withdrawn from theannulus A on a first side of the fissure F. More particularly, at thispoint in the procedure, axial tension has been applied to the distal endof the flexible longitudinal fixation component 110 so as to pull thefirst transverse anchor component through nucleus tissue.

FIG. 3 is a schematic view showing the apparatus 101 in the nucleustissue and the needle-like insertion device withdrawn from the annuluson a first side of the fissure. More particularly, at this point in theprocedure, additional axial tension has been applied to the distal endof the flexible longitudinal fixation component 110 so as to pull thefirst transverse anchor component 102 through nucleus tissue and backagainst the inner surface S of the posterior annulus. This may be doneby pulling on the distal end of flexible longitudinal fixation component110 in a direction perpendicular to the posterior wall of the annuluswith a force of about 15N to 25N so as to pull the first transverseanchor component 102 back through the intervening nucleus material sothat the first transverse anchor component 102 seats securely againstthe inner surface of the posterior annulus. It has been discovered thata force of this direction and magnitude is needed to reliably move thefirst transverse anchor component 102 through the heavy crabmeat-likeconsistency of the nucleus N.

FIG. 4 is a schematic view showing needle-like insertion device 122advancing a portion of the apparatus 101 through the annulus A of theintervertebral disc D on a second side of a tear or fissure F and intothe nucleus tissue N. The distal 5 to 25 millimeters of the needle-likeinsertion device 122 may preferably be curved in alternative embodimentsof the invention. In addition, the stylet component 127 in the lumen ofthe needle-like insertion device 122 forces the second transverse anchorcomponent 104 from the distal end of the needle-like insertion device122 after the distal end of the needle-like insertion device 122 haspassed through the posterior annulus on a second side of the fissure F,which is generally opposite to the side on which the previously-insertedtransverse anchor component 102 was set. It will be appreciated that asthis occurs, a length 11 of the flexible longitudinal fixation component110 will extend laterally across the fissure F.

Again, when the second transverse anchor components 104 is ejected fromthe distal end of the needle-like insertion device 122 into the nucleusN, the distal end of the needle-like insertion device 122 must have beenadvanced a sufficient distance into the nucleus N for the secondtransverse anchor components 104 to be able to turn (i.e., from thelongitudinal orientation of FIG. 4 to the transverse orientation ofFIGS. 5 and 6) so as to prevent the second transverse anchor component104 from being pulled back through the annulus. Note also that at thislevel of penetration into the nucleus, a substantial amount of nucleusmaterial will be interposed between the second transverse anchorcomponent 104 and the inner surface of the posterior annulus.

Again, axial tension is applied to the flexible longitudinal fixationcomponent 110 to pull the second transverse anchor components 104through the nucleus tissue and back against the inner surface of theposterior annulus. This may be done by pulling on the distal end of theflexible longitudinal fixation component 110 in a directionperpendicular to the posterior wall of the annulus with a force of about15N to 25N so as to pull the second transverse anchor component 104 backthrough the intervening nucleus material so that the second transverseanchor component 104 seats securely against the inner surface of theposterior annulus. It has been discovered that a force of this directionand magnitude is needed to reliably move the second transverse anchorcomponent 104 through the heavy, crabmeat-like consistency of thenucleus N.

FIG. 5 is a schematic view showing the apparatus 101 in the nucleustissue and the needle-like insertion device 122 withdrawn from theannulus A on a second side of the fissure F. More particularly, at thispoint in the procedure, axial tension has been applied to the distal endof the flexible longitudinal fixation component 110 so as to pull thesecond transverse anchor component through the nucleus tissue. A portion111 of the flexible longitudinal fixation component 110 extends betweenthe first and second transverse anchor components 102 and 104,respectively. The central portion 120 and distal portion 130 of theflexible longitudinal fixation component 110 are seen extending axiallythrough the hole 140 formed in the annulus A by the needle-likeinsertion device 122.

As shown in FIG. 6, axial tension applied to the distal end of theflexible longitudinal fixation component 110 pulls the second transverseanchor component 104 against the inner surface of the posterior annulusand reduces the length of portion 111 of the flexible longitudinalfixation component 110. Again, this tension should be applied axially(i.e., substantially perpendicular to the posterior wall of theannulus), and at a substantial level (e.g., at about 15N to 25N), inorder to ensure proper seating of the transverse anchor component 104against the inner surface of the posterior annulus.

Once the transverse anchor component 104 has been properly seatedagainst the inner surface of the posterior annulus (i.e., once thetransverse anchor components 102 and 104 have been “pre-tensioned”),additional axial tension on the distal end of the flexible longitudinalfixation component pulls distal end of the central portion 120 of theflexible longitudinal through the opening or openings in anchor 104,which applies lateral tension on that portion of the flexiblelongitudinal fixation component so as to draw the fissure F closed, andthen the central portion 120 and distal portion 130 of the flexiblelongitudinal fixation component 110 may be locked into the opening oropenings in anchor 104.

More particularly, FIG. 6 is a schematic view showing how tension (e.g.,about 15N to 25N) applied axially to the distal end 134 of the flexiblelongitudinal fixation component 110 tightens the central portion 111 ofthe flexible longitudinal fixation component 110, which extendslaterally over the fissure or defect F in the annulus. The distal end134 of the flexible longitudinal fixation component 110 is preferablycut flush with the posterior surface 150 of the annulus in the next stepof the procedure. Alternatively, as shown in FIGS. 8, 9, and 10, third,fourth, fifth or more anchors, through which the flexible longitudinalfixation component 110 passes may be passed through the annulus usingthe same method before the distal end 134 of the flexible longitudinalfixation component 110 is cut and removed.

Thus it will be seen that, with the present invention, a filament (e.g.,the flexible longitudinal fixation component 110) is used to laterallyspan a tear, fissure or other defect in the annulus, with one portion ofthe filament being anchored to the annulus by passing at least one firstanchor (e.g., a transverse anchor component) through the annulus andinto the nucleus on one side of the fissure, and with a second portionof the filament being anchored to the annulus by passing at least onesecond anchor (e.g., a transverse anchor component) through the annulusand into the nucleus on a second side of the fissure, with the at leastone first and second anchors being drawn back through the nucleus andagainst the inner surface of the posterior annulus by the application ofa significant (e.g., about 15N to 25N) axial tension appliedperpendicular to the posterior wall of the annulus (i.e., by a“pre-tension”), and with the fissure being drawn closed by thesubsequent application of a significant (e.g., about 15N to 25N) axialtension applied perpendicular to the posterior wall of the annulus(i.e., by a “closing tension”), and with portions of the filamentsthereafter being secured to one or more anchors (e.g., by press fit intoslots in the second anchor) so as to hold the fissure closed.

FIG. 7 is a schematic view showing the surface 150 of the posteriorannulus and the flexible longitudinal fixation component 110 inposition. The distal end 134 of the flexible longitudinal fixationcomponent 110 is seen extending through hole 140 in the annulus. Hightension on the flexible longitudinal fixation component 110 creates astiff construct spanning the fissure F, which resists pressure from thenucleus N trying to extrude through the closed fissure F.

FIG. 8 is a schematic view showing the surface 150 of the posteriorannulus and the flexible longitudinal fixation component 110 in analternative embodiment of the invention shown in FIG. 7. Flexiblelongitudinal fixation component 110 extends from a first anchor placedin the caudal portion of the annulus on the left side of the fissure toa second anchor placed in the caudal portion of the annulus on the rightside of the fissure then to a third anchor placed in the cranial portionof the annulus on the left side of the fissure then to a fourth anchorplaced in the cranial portion of the annulus on the right side of thefissure.

The second, third, and fourth anchors have features that permit slidingof portions of flexible longitudinal fixation component 110 throughthose anchors then fastening or locking of portions of flexiblelongitudinal fixation component 110 to those anchors. Axial tension ofabout 15N to 25N or more is preferably applied to the distal end offlexible longitudinal fixation component 110 following insertion of eachsuch anchor so as to pull each anchor through the nucleus and againstthe inner layer of the annulus and to reduce the length of the centralportions of flexible longitudinal fixation component 110, which narrowsthe fissure in the annulus. Locking portions of flexible longitudinalfixation component 110 in two or more anchors maintains tension on mostof the flexible longitudinal fixation component 110 should lockingmechanisms in one or two anchors fail.

FIG. 9 is a schematic view showing an alternative embodiment of thepresent invention. More particularly, FIG. 9 shows flexible longitudinalfixation component 210 passing from a first anchor 902 placed behind theannulus cranial on the left side and above transverse fissure F to asecond anchor 904 placed in the cranial portion of a vertebra V, then toa third anchor 906 placed behind the annulus cranial to a transversefissure on the right side of that fissure. The first and third anchorshave the locking feature.

In FIG. 10, the flexible longitudinal fixation component 310 passes froma first anchor placed behind the annulus caudal to a transverse fissureon the left side of that fissure to a second anchor placed in behind theannulus cranial to the transverse fissure on the left side of thatfissure followed by third, fourth, fifth, and sixth anchor placedsequentially caudal then cranial to the fissure in the annulus. Thesecond through sixth anchors have the locking feature. Five, seven,eight, or more anchors connected by a single flexible longitudinalfixation component can be used in alternative embodiments of theinvention. Alternatively, two or more flexible longitudinal fixationcomponents connecting at least two anchors each could be used inalternative embodiments of the invention. As with other embodimentsdescribed herein, considerable axial tension is applied to the flexiblelongitudinal fixation component 310 to seat each anchor prior todeployment of the next.

Anchors that permit sliding of portions of one or more flexiblelongitudinal fixation components through such anchors then locking orfastening of portions of such one or more flexible longitudinal fixationcomponents are used in preferred embodiments of the invention. Preferredanchors could have cleat mechanisms or alternative locking mechanisms.For example, elastic projections from the sides of openings in theanchors could permit sliding of flexible longitudinal fixationcomponents in a first or tightening direction, but prevent sliding ofthose flexible longitudinal fixation components from sliding in theopposite direction.

Anchors made of shape memory materials such as Nitinol may be used incertain embodiments of the invention. Alternatively, removable elongatecomponents could hold elastic projections from the sides of openings inanchors in an “open” position, which permits sliding of flexiblelongitudinal fixation components through the anchors. Removal of suchelongate projections after tightening the flexible longitudinal fixationcomponents allows the elastic projections to move thereby trapping theflexible longitudinal fixation component between the elastic projectionsand other portions of the anchor, which fastens or locks the flexiblelongitudinal fixation component to the anchor.

FIG. 11 is superior view of a partial longitudinal cross section apreferred form of apparatus for closing the fissure in the annulus. Aportion of the flexible longitudinal fixation component 110 is seenpassing through a hole in transverse anchor component 1102. A projection1104 from one side of the transverse anchor component permits theflexible longitudinal fixation component to easily slide through theanchor component in a first direction indicated by the arrow, but resistsliding of the flexible longitudinal fixation component in a seconddirection.

FIG. 12 is a superior view of a flexible longitudinal fixation component(not shown) passes through two openings in transverse anchor component1202. Projections 1204, 1206 into the openings in the transverse anchorcomponent permit the flexible longitudinal fixation component to easilyslide through the anchor in the directions shown, but resist sliding ofthe flexible longitudinal fixation component in the opposite direction.The projection components 1204, 1206 could preferably be made of firstmaterial, such as titanium while the transverse anchor component is madeof a second material, such as PEEK. The anchor component of FIG. 12 maybe used for either of the anchors 102, 104 shown in FIG. 6, for example.

FIG. 13 is a superior view of a longitudinal cross section of anchor1302. Projections 1304, 1306 are seen extending from two portions oftransverse anchor component 1302. The projections permit the flexiblelongitudinal fixation component to easily slide through the anchorcomponent in a first direction depicted with the arrow, but resistsliding of the flexible longitudinal fixation component in a seconddirection.

FIG. 14 is a superior view of a further alternative anchor component1402. Two holes 1404, 1406, are shown passing through transverse anchorcomponent 1402. The generally circular lateral portions of the holes arelarger than the narrow slit-like medial portions 1408, 1410 of thoseholes. The transverse anchor components 102 is preferably about 0.8 to 2millimeters in diameter, and most preferably about 1.1 to 1.3millimeters in diameter, and about 3 to 7 millimeters in length, andmost preferably about 4 to 5 millimeters in length. The holes intransverse anchor component 102 are preferably about 0.1 to 0.8millimeters in diameter, and most preferably have a narrow portion ofabout 0.1 to 0.3 millimeters in diameter and wider portion of about 0.4to 0.8 millimeters. The flexible longitudinal fixation component (notshown) slides easily through the transverse anchor component whenflexible longitudinal fixation component resides in the largercircular-like portions of the holes. The flexible longitudinal fixationcomponent is forced into the narrow slit-like openings of the transverseanchor component to prevent or restrict such sliding after tensioningthe flexible longitudinal fixation component. FIGS. 15-17 illustratealternate slit configurations.

It should be understood that many additional changes in the details,materials, steps and arrangements of parts, which have been hereindescribed and illustrated in order to explain the nature of the presentinvention, may be made by those skilled in the art while still remainingwithin the principles and scope of the invention.

1. A method of closing a fissure or other defect in an annulus fibrosus(AF) having an outer surface and an inner surface, the method comprisingthe steps of: providing a flexible longitudinal fixation componentterminating in a distal end coupled to a first anchor component, and aproximal second anchor component slidingly coupled along the flexiblelongitudinal fixation component; inserting the first anchor componentthrough a first insertion point in the AF from the inside out on oneside of the defect in the AF such that the first anchor component passesthe inner surface of the AF and a first exposed portion of the flexiblelongitudinal fixation component extends outwardly from the firstinsertion point; applying tension to the first exposed portion of theflexible longitudinal fixation component such that the first anchorcomponent becomes firmly seated against the inner surface of the AF;inserting the second anchor component through a second insertion pointin the AF from the inside out on the other side of the defect in the AFsuch that the first exposed portion crosses over the defect and into thesecond insertion point, and a second exposed portion of the flexiblelongitudinal fixation component extends outwardly from the secondinsertion point; and applying tension to the second exposed portion suchthat the flexible longitudinal fixation component slides through thesecond anchor component, applying tension to the first exposed portion,thereby closing the defect in the AF and causing the second anchor tobecome firmly seated against the inner surface of the AF.
 2. The methodof claim 1, wherein the tension applied to the first exposed portion isin the range of about 15 N to 25 N.
 3. The method of claim 1, whereinthe tension applied to the second exposed portion is in the range ofabout 15 N to 25 N.
 4. The method of claim 1, wherein the flexiblelongitudinal fixation component is a surgical suture.
 5. The method ofclaim 1, wherein the at least the second anchor component includes aphysical feature that prevent further sliding of the flexiblelongitudinal fixation component following the step of applying tensionto the second exposed portion.
 6. The method of claim 1, wherein the atleast the second anchor component includes one or more barbs orprojections that prevent further sliding of the flexible longitudinalfixation component following the step of applying tension to the secondexposed portion.
 7. The method of claim 1, wherein the at least thesecond anchor component includes one or more barbs or projections thatprevent further sliding of the flexible longitudinal fixation componentfollowing the step of applying tension to the second exposed portion. 8.The method of claim 1, wherein the process is repeated with one or moreadditional anchors slidingly coupled at different points along theflexible longitudinal fixation component such that two or more exposedportions cross the defect when the process is completed.
 9. The methodof claim 1, wherein the one or both of the anchor components areelongated such that they penetrate the AF axially and turn once past theinner surface of the AF to better prevent pull-out.
 10. The method ofclaim 1, wherein the one or both of the anchor components are insertedwith a pointed, cannulated insertion instrument that penetrates the AFand deploys each anchor component with a stylus or push rod.
 11. Themethod of claim 1, including the step of anchoring the flexiblelongitudinal fixation component to one of an upper and lower vertebralbody.
 12. The method of claim 1, including the step of trimming thesecond exposed portion of the flexible longitudinal fixation component.13. Apparatus for repairing a defect in the annulus fibrosus, theapparatus comprising: a flexible longitudinal fixation componentcomprising a proximal end and a distal end; at least one anchorcomponent slidingly coupled to the flexible longitudinal fixationcomponent; wherein the at least one anchor component comprises a holefor receiving the flexible longitudinal fixation component, and furtherwherein the at least one anchor component comprises a physical featurefor (i) permitting the flexible longitudinal fixation component to slidethrough the hole in a first direction, and (ii) preventing the flexiblelongitudinal fixation component from sliding through the hole in asecond direction.
 14. Apparatus according to claim 13 wherein theflexible longitudinal fixation component comprises suture.
 15. Apparatusaccording to claim 13 wherein the anchor component is elongate with anon-circular cross-section.
 16. Apparatus according to claim 13 furthercomprising a pointed, cannulated insertion instrument for penetratingthe annulus fibrosus and deploying the at least one anchor componentwith a stylus or push rod.
 17. Apparatus according to claim 13 whereinthe anchor component comprises Nitinol.
 18. Apparatus according to claim13 further comprising a second anchor component coupled to the distalend of the flexible longitudinal fixation component.
 19. Apparatusaccording to claim 13 wherein the hole is substantially perpendicular tothe longitudinal axis of the anchor component.
 20. The apparatus ofclaim 14 wherein the anchor component comprises two holes, and furtherwherein the two holes are substantially perpendicular to thelongitudinal axis of the anchor component.
 21. Apparatus according toclaim 13 wherein the physical feature comprises at least one from thegroup consisting of a barb, a projection, a cleat and a narrow portionwithin the hole.